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I've searched a thousand threads and read a thousand more and haven't found the solid answer I'm seeking.
What does one need to do to prevent the door lock plungers from double flashing? Any specific wire I need to either connect or isolate or join with another, and if so, color and location would be helpful and most appreciated.
All the alarm trip points need to be engaged, to get the single slow flash.
Double flash means one of the alarm points is tripped or not being reset.
From memory:
Rear Hatch, one shock arm reed trip (grounds to shock piston when opened)
Micro switch in hood latch, must remain depressed when hood is in closed position, very little tollerance, if reed bends, or switch mount is loose, it will not move the 1mil down to mark the alarm as armed.
Glove box (It is in the light switch I think, must be depressed fully)
Driver Door locks (I assume the microswitch in the locks, which is engaged when car is locked)
Passenger Door locks (I assume the microswitch in the locks, which is engaged when car is locked)
Radio (I can not remember if it grounds when radio is removed, and floats when not armed, I seem to remember as the radio slides out, a reed will contact the radio, causing a ground and tripping alarm)
If any of these points malfunction, alarm will not fully activate with the single flash in the lock *****.
I can look it all up again if you want me to dig through my 968 service manual for troubleshooting the alarm.
I went through this 2 years ago, was my hood microswitch for the alarm was my culprit. An unplugged hood light was the clue from the previous PO, as that left the hood light on all the time, which drained the battery. If the microswitch is not depresed, alarm will not fully arm or that zone, and the engine bay light stays on.
Pretty sure my radio alarm wire is just taped off. Not 100% either way it is either supposed to ground for alarm, or unground.
So I forgot to add, this system is unique to the 968 and is not the same of any of the 944s. Every time the system is activated, it checks all the alarm trigger points. The alarm will still activate, but if something fails that check, such as the rear hatch is open, that point will no longer activate the alarm. That is why you get the double flash, pause, double flash.
Of you have a ODBII to the ODBI adapter, durametric will read the codes for you and clear the fault memory.
The full diagnostics sheets are geared towards having a special tool to test components, but are useful, and about 10 pages long. Here is a quick cheat sheet of sorts to help you out.
What I never noticed before, and find interesting, is there are 3 more analog terminals you can use, to trip the alarm, I assume for a motion sensor, or level to detect if car is towed, etc. Pretty cool!
Wonder if Jeff ever heard of such options?
I used I think pins 10 and 12 to tie my 5 dollar ebay keyless entry module, to lock and unlock the factory alarm.
I have only locked my car once and I noticed that the drivers door **** didn't flash but the passenger side did double time. I have a new diode assembly with the **** but it's low on the list....like 2018.
I assumed there would be less parasitic draw off the battery with it left unlocked....the hoods up all the time anyway))
I found some other notes, says 91 on all Porsches had this system at the time. The 3 quick arm forces the system to arm, if you have a problem.
Function of the alarm system
With the ignition key removed, the alarm can be activated in two ways.
1. Locking one of the door locks which also simultaneously operates the central locking (passive activation).
2. Locking one of the door locks rapidly three times in succession (active activation).
"Active activation" allows the alarm system to be switched on even if the central locking is faulty. The alarm control unit requires 3 activating impulses to recognize that the alarm system is to be activated despite a door that cannot be locked.
After activation of the alarm, all triggering circuits (alarm contacts) are checked to ensure that they are in proper working order. If no fault is recognized, this is indicated by rapid flashing of the LED's in the locking ***** for approx. 10 seconds (self-test).
After 10 seconds all alarm circuits are activated. The LED's in the locking ***** indicate this by slow flashing.
If a fault is recognized during the check (e.g. engine hood open, switch defective etc.), no confirmation takes place by means of rapid flashing of the LED's on the central locking *****. After the 10 seconds, only the fault-free triggering circuits are activated. The LED's in the central locking ***** indicate this by double flashing.
If the recognized fault is eliminated (e.g. engine hood is closed), the triggering circuit concerned is activated after a 10 second delay. The LED's in the central locking ***** indicate this by slow flashing. A triggering circuit is activated if it is in its basic position for at least ten seconds without interruption.
If an alarm has been set off, this is indicated by double flashing until the alarm is deactivated.
If the tailgate is unlocked while the alarm is on, then the alarm will be deactivated. 10 seconds after the tailgate has been reclosed, the alarm system is automatically reactivated.
To prevent unintended switching on of the alarm, the speedometer signal as well as terminal 15 and terminal 61 is evaluated.
Thanks for the replies everyone. I've got most of this already covered, and now I just need the "dis/connect the x-colored wire from the back of the radio" advice. I read in a number of places also that the radio alarm sensor will trip on completing the circuit, with a reed making that connection went the radio is pulled. When an aftermarket radio gets installed, most installers make all the connections and inadvertently close that circuit by doing so, which causes the alarm module to see the radio as missing during alarm activation and responding with the double flash notification.
Have you messed with your glovebox light? I have heard of people hooking this up backwards for the switch, causing an issue with the alarm.
Either way, I am confident, that you do not want to ground the radio alarm wire at all.
As for color, not sure. Are all your connectors gone? It was just a single brown/blue wire I think with a blade receptacle.
This is the wiring diagram from a 93 coupe, it says .5 BR/BL ? What colors are those? What year is your car, I can see if it is different.
Originally Posted by Vendetta NY
Thanks for the replies everyone. I've got most of this already covered, and now I just need the "dis/connect the x-colored wire from the back of the radio" advice. I read in a number of places also that the radio alarm sensor will trip on completing the circuit, with a reed making that connection went the radio is pulled. When an aftermarket radio gets installed, most installers make all the connections and inadvertently close that circuit by doing so, which causes the alarm module to see the radio as missing during alarm activation and responding with the double flash notification.
Public thanks, Touareg. Got the car back from the installer a week ago - still doin' the double flash thing and I'm certain it's the alarm wiring to the radio chassis. I might get into it over the winter, might not. But I'm subbing to this thread to keep the info within easy reach.
11-21-2015, 10:26 PM
Help needed: Alarm wire to stereo
